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Biomedical subjects

C J Baker

Publications and source records attributed to C J Baker.

At least 217 records · Page 12Linked to original sources
PubMed1981

Antibody to group B Streptococcus type III in human sera measured by a mouse protection test.

Antibody to group B Streptococcus type III (GBS-III) was measured in human plasma and sera by using a test which measures the ability to protect outbred albino mice from an intraperitoneal challenge of GBS-III calculated to be lethal to 90% of the mice (LD90 dose). Of three samples from three different lots of commercial human immune serum globulin, none were protective despite the presence of antibody to the native type III polysaccharide. Nine specimens were tested from recipients of multivalent pneumococcal vaccine, and none were protective. Five specimens were tested from recipients of GBS-III polysaccharide vaccines who had responded with greater than 50 micrograms of specific antibody per ml in the blood. All of these were protective and could be diluted to titers of 1:10 to 1:40. Of two prevaccination sera with low levels of specific antibody, neither was protective. An unexpected finding which may limit the sensitivity of the mouse protection assay was that the human immune serum globulin and human serum with a very low level of antibody appeared to increase the lethality of the GBS-III test strain, resulting in LD50 values reduced to 0.01 of the usual LD50.

Animals↗
PubMed1981

Intraamniotic infection due to group G streptococcus: treatment and antibody response.

Penicillin treatment and antibody response were studied using a rhesus monkey model for intraamniotic infection with type III group B streptococci (T3GBS). Acute and convalescent phase sera from mothers and their offspring were tested with a radioactive antigen-binding assay to determine the concentration of antibody to the capsular T3GBS antigen. The frequency of placentitis was significantly lower in penicillin-treated animals (3 of 8) than in controls (10 of 10; P less than .01). The penicillin group also had a significantly lower neonatal mortality (1 of 9) than controls (6 of 10; P less than .05). Both groups of rhesus mothers developed a significant increase in concentration of antibody to T3GBS, but the antibody response was of lesser magnitude in the penicillin-treated group. This experimental model appears to be useful for studying both therapy for intraamniotic infection and the humoral immune response to infection with T3GBS.

Amnion↗
PubMed1981

Role of antibody to native type III polysaccharide of group B Streptococcus in infant infection.

The role of maternally acquired antibody to native type III polysaccharide of group B Streptococcus as a determinant of susceptibility for infant systemic infection was investigated. Sera from 111 acutely ill infants with type III group B streptococcal bacteremia and/or meningitis and their mothers, and cord sera from 45 healthy neonates and their mothers who had type III group B streptococcal vaginal colonization at delivery were studied. Sera from each of 111 acutely ill infants contained very low levels of antibody (less than 1.7 microgram/ml, median 0.4 microgram/ml), and a significant correlation with maternal levels was tested for early onset infection (median 0.6 microgram/ml; 4 = .76; P less than .01). Women whose infants remained well had antibody levels greater than 2 microgram/ml in their sera (73%) more often than those whose infants developed symptomatic infection (17%) (P less than .001), and the median level in their sera (12.6 microgram/ml) was considerably higher. Study of sera obtained during convalescence from 86 surviving infants indicated a poor antibody response to infection. In contrast, high levels of antibody were detected in sera from each of five convalescent women with postpartum bacteremia. These data extend earlier observations suggesting the correlation between low levels of type-specific antibody in serum and risk for systemic infection with type III strains of group B streptococci.

Antibodies, Bacterial↗
PubMed1980

Influence of preimmunization antibody levels on the specificity of the immune response to related polysaccharide antigens.

We studied the influence of preimmunization antibody level on the immune response of adults to one of two structurally related yet immunologically distinct type-specific polysaccharides from Type III Group B streptococcus and Type 14 pneumonococcus. Four weeks after immunization with multivalent pneumococcal vaccine, 20 subjects with low levels of antibody to Type III Group B streptococcus antigen had no significant increase in antibody to this antigen (P greater than 0.05), but all volunteers with moderate to high preimmunization antibody levels who were immunized with Pneumovax had significant increases (P less than 0.01). However, the streptococcal antibody response to pneumococcal Type 14 antigen was weaker and briefer than that in 10 adults given Type III Group B streptococcus vaccine(P less than 0.05). Preimmunization antibody levels influenced the immune response to a structurally similar polysaccharide antigen, but specific Type III polysaccharide antigen appeared necessary to induce a primary antibody response in "nonimmune" adults. We conclude that immunization of mothers with pneumococcal vaccine is not likely to prevent neonatal Type III Group B streptococcal infection, despite immunologic similarities between the two organisms.

Adult↗
PubMed1980

The natural history of group B streptococcal colonization in the pregnant woman and her offspring. II. Determination of serum antibody to capsular polysaccharide from type III, group B Streptococcus.

An investigation of the prevalence and persistence of the concentration of antibody to capsular polysaccharide from type III, group B Streptococcus in sera from 93 pregnant women and their newborn infants is reported. In the majority of women, the concentrations of antibody detected in the sera were low (less than 1 microgram/ml). However, sera from women who were colonized with type III strains of group B streptococci contained significantly higher concentrations of antibody than those from noncolonized women (p = 0.027). No appreciable change in antibody concentration was found in sera collected early in gestation when compared to delivery sera. When maternal-cord serum pairs were analyzed, a significant correlation between concentrations of antibody was found, which indicates that this antibody is transplacentally transferred.

Antibodies, Bacterial↗
PubMed1980

The role of specific antibody in alternative complement pathway-mediated opsonophagocytosis of type III, group B Streptococcus.

The native capsular polysaccharide antigen of type III, group B Streptococcus contains a terminal sialic acid residue on each repeating unit that masks all end-group galactopyranose residues and prevents alternative pathway complement activation by adult human sera in the absence of type-specific antibody. The critical role of the sialic acid residues in allowing the organism to evade activating the alternative complement pathway was shown when neuraminidase treatment of the organism converted the bacteria to activators of the alternative pathway as assessed in agammaglobulinemic serum. The requirement for specific antibody in permitting alternative pathway activation by the fully sialated bacteria was shown when sera that contained low levels of specific antibody failed to activate this pathway, and when prior absorption of serum that contained higher type-specific antibody levels with the capsular antigen failed to activate this pathway. The use of C2-deficient sera showed that the calssical pathway was not required for antibody-dependent alternative pathway activation. The use of isotonic, pH 7.5, veronal-NaCl buffer that contained 1% gelatin and that was supplemented to 4 mM Mg++ and 16 mM EGTA and adjusted to pH 7.5 (MgEGTA) ruled out the participation of the C1-bypass pathway. The presence of sialic acid on the bacterial surface is one means of evading an important mechanism of natural immunity, namely activation of complement by the alternative pathway. Only specific antibody, i.e., acquired immunity, can overcome this virulence factor.

Antibodies, Bacterial↗
PubMed1980

Luminol-enhanced chemiluminescence for evaluation of type III group B streptococcal opsonins in human sera.

A luminol-enhanced chemiluminescence (CL) assay was developed to evaluate type III group B streptococcal opsonins. Sera from 11 adults that contained high (greater than 25 microgram/ml), intermediate (3-24 microgram/ml), or low (less than 2 microgram/ml) antibody concentrations were assessed by CL, indirect immunofluorescence (IF), and bactericidal assays. Total CL activity correlated with antibody concentration (P less than 0.005), IgG- and C3-IF values, and phagocytic and bactericidal indices. Heat-stable CL activity correlated with antibody concentration (P less than 0.0001) and was related to IgG-IF values and phagocytic indices. Significant bactericidal activity was demonstrated in all sera containing greater than 2 microgram of antibody/ml, but no bactericidal activity was observed in heat-inactivated sera. Adsorption of heated sera with type III group B Streptococcus abolished CL activity, whereas CL values of MgEGTA-chelated sera were approximately 80% of untreated sera. Thus, type-specific antibody in addition to heat-labile serum factors, including those of the alternative complement pathway, contribute to opsonization of type III group B Streptococcus.

Antigen-Antibody Reactions↗
PubMed1980

Comparison of slide coagglutination test and countercurrent immunoelectrophoresis for detection of group B streptococcal antigen in cerebrospinal fluid from infants with meningitis.

The usefulness of Phadebact streptococcus reagents for the detection of group B streptococcal antigen in cerebrospinal fluid was evaluated in 54 infants with meningitis and in 22 normal infants. Antigens was detected by slide coagglutination in 19 (82.6%) and by countercurrent immunoelectrophoresis in 20 (87.0%) of 23 cerebrospinal fluid specimens from infants with group B streptococcal meningitis at admission. After initiation of antimicrobial therapy, antigen could be detected in 11 of 19 (by slide coagglutination) and 7 of 18 (by countercurrent immunoelectrophoresis) cerebrospinal fluids. False-positive reactions were noted by slide coagglutination in one infant with S. bovis meningitis and one with group B streptococcal bacteremia without meningitis; none occurred with countercurrent immunoelectrophoresis. The commercial availiability, simplicity, sensitivity (82.6%), and specificity (96.4%) of the Phadebact slide coaggluatination test for detecting group B streptococcal antigen in cerebrospinal fluid suggest that it may be useful for the early and rapid diagnosis of group B streptococcal meningitis.

Agglutination Tests↗
PubMed1980

Commercial latex agglutination test for rapid diagnosis of group B streptococcal infection in infants.

Although latex agglutination assays for detection of a variety of bacterial antigens in body fluids from patients with systemic infection have been shown to be useful as rapid diagnostic techniques, lack of commercial availability has restricted their application. The Streptex latex test kit for the detection of group B streptococcal (GBS) antigen in admission body fluid specimens was evaluated for sensitivity and specificity in 54 infants with meningitis and in 10 infants with normal cerebrospinal fluid (CSF) parameters. GBS antigen was detected in 22 of 28 (78.6%) CSF specimens by latex agglutination and in 23 of 28 (82.1%) by countercurrent immunoelectrophoresis. Antigen was present in 21 of 28 (latex agglutination) and 19 of 26 (countercurrent immunoelectrophoresis) CSF specimens after the initiation of antimicrobial therapy. Heat-labile factors accounted for nonspecific agglutination reactions with latex suspensions other than group B in 3 of 28 CSF samples from patients with GBS meningitis. These nonspecific reactions were readily eliminated by heating specimens for 10 min at 100 degrees C. Fifteen patients with GBS meningitis had admission serum and urine samples collected in addition to CSF. Antigen was detected by latex agglutination and countercurrent immunoelelectrophoresis in 14 of 15 (93.3%) and 13 of 15 (86.7%) concentrated urine specimens, respectively, and in 12 of 15 (80%) CSF specimens and 4 of 15 (27%) sera by each method. These findings indicate that the Streptex latex test is a rapid, sensitive, and readily available method for detection of GBS antigen in admission body fluid specimens from infants with meningitis.

Antigens, Bacterial↗
PubMed1980

Countercurrent immunoelectrophoresis in the evaluation of infants with group B streptococcal disease.

Admission specimens of CSF, serum, and urine from 67 patients with proved group B streptococcal (GBS) bacteremia and/or meningitis were evaluated by countercurrent immunoelectrophoresis (CIE). Group B and type-specific antigens were detected in 81% of CSF, 63% of serum, and 96% of concentrated urine specimens by CIE. Each of 26 infants with meningitis from whom all three body fluids were available and ten with bacteremia from whom both serum and urine were collected at admission had GBS antigens detected by CIE in at least one specimen. No false positive reactions were observed. Among patients with type III, GBS meningeal infection, fatal outcome or neurologic sequelae were significantly correlated with concentration of type III antigen in admission CSF and duration of antigenuria when compared to normal survivors (P = less than .05, Mann-Whitney U tests). CIE appears to be a useful diagnostic and prognostic tool for infants with GBS infection if admission specimens from more than one source are examined and appropriately high-titered antisera are employed for testing.

Antigens, Bacterial↗
PubMed1979

Immunodeterminant specificity of human immunity to type III group B streptococcus.

The type III polysaccharides of group B Streptococcus in its native state chemically consists of glucose, galactose, glucosamine, and sialic acid. The core of this polysaccharide lacks sialic acid and precipitates with type III antiserum to give a partial identity with the precipitate between the native antigen and this serum. The core determinant is immunochemically similar to the capsular polysaccharide of type XIV Streptococcus pneumoniae, while the native type III group B streptococcal polysaccharide does not cross-react with type XIV pneumococcal antiserum. In human sera, it is antibody directed to the native antigen which correlates very highly with opsonic immunity (r = 0.94) while a poorer correlation exists between antibody to the core antigen and opsonins (r = 0.51 P less than 0.001). In natural infections, as association exists between low levels of maternal antibody to the native antigen and risk of disease in the infant. This association is not true for antibody to the core structure, where both infected infants and their mothers have much higher levels of antibody to the core than the native antigens. Infected infants are also more likely to respond to infection by developing antibody to the native antigen. Immunization of 12 adults with multivalent pneumococcal polysaccharide induced significantly better antibody response to the core antigen than to the native, and this vaccine induced opsonic activity in only one recipient. Immunization of adults with type III group B streptococcal antigens induced antibody to the native determinant which correlated with opsonic activity. Therefore, it would appear that native group B streptococcal polysaccharides will provide the best candidate antigens for immunization.

Antibodies, Bacterial↗
PubMed1979

Group B streptococcal colonization and antibody status in lower socioeconomic parturient women.

This investigation was undertaken to determine the prevalence of group B streptococcal vaginal and throat colonization among lower socioeconomic pregnant women and the antibody concentration to the capsular polysaccharide antigen of type III group B streptococcus in their sera. Group B streptococci were recovered from 28.6 per cent of the 112 women studied; vaginal colonization was detected in 23.4 per cent, throat colonization in 4.7 per cent, and colonization at both sites in 0.9 per cent of the patients, respectively. Among these isolates of group B streptococci, serotypes III (39.5 per cent) and II (30.3 per cent) predominated. No differences were found between colonized and noncolonized women with respect to age, race, marital status, or parity. The majority of all women studied had low concentration of antibody in serum (less than 1.0 microgram per milliliter). However, women with isolation of type III group B streptococci from cultures at the time sera were collected had significantly higher concentrations than did women without group B streptococci from cultures at the time sera were collected had significantly higher concentrations than did women without group B streptococcal colonization.

Adolescent↗
PubMed1979

Endophthalmitis associated with Haemophilus influenzae type b bacteremia and meningitis.

The unusual occurrence of endophthalmitis associated with Haemophilus influenzae type b bacteremia and meningitis was confirmed in three young children during a five-year period. In contrast to bacterial endophthalmitis attributed to other microorganisms, these three infections resolved completely within a few days with conventional antimicrobial therapy. Endophthalmitis is but one of the apparently increasing number of unsuual complications that may be observed as a result of H influenzae type b bacteremia.

Administration, Topical↗
PubMed1979

Rapid diagnosis of type III group B streptococcal meningitis by latex particle agglutination.

A latex particle agglutination assay was developed to detect type III group B streptococcal antigen in cerebrospinal fluid. Agglutination was observed in each of 12 initial and 54% of 26 subsequent CSF specimens obtained a mean of 53 hours after the institution of antimicrobial therapy. Latex agglutination was more sensitive than countercurrent immunoelectrophoresis for the detection of type III group B streptococcal antigen in CSF from neonates and young infants with meningitis.

Antigens, Bacterial↗
PubMed1979

Electron microscopic definition of surface antigens of group B Streptococcus.

Strains representing each of the five serologically distinct types of group B Streptococcus and variant strain 090R, which is devoid of type-specific polysaccharide, were studied by electron microscopy after incubation with various ferritin-conjugated antibodies. Ferritin-conjugated types Ia, II and III antibodies localized on homologous cells in a pattern that defines the capsular location of the type Ia, II, and III polysaccharide antigen. Type Ib and Ic cells have surface antigens to which ferritin-labeled antibodies to both capsular polysaccharide and a common surface protein attach.

Animals↗